Climate change and the intensification of anthropogenic activities in watersheds have been substantially changing the streamflow regime, which is a problem for water resource managers. This study assesses the influence of the changes in land use and land cover and rainfall on the streamflow regime. This study also models the pattern of these streamflows according to the rainfall and land use and land cover in the Santo Antônio River watershed, located in the transitioning region of the Brazilian Biomes Atlantic Forest and Cerrado. To assess the dynamic relationship between land use and land cover and the streamflow regime, five classes of land use and land cover were used. To characterize the hydrological pattern, data from six streamflow gauges and 24 rainfall gauges that influence the study area were used. Multiple regression models were adjusted to estimate streamflow using the explanatory variables rainfall and land use and land cover. As result, a direct relationship was found, as the decrease in streamflow in some drainage areas was influenced by the decrease in rainfall over the base period. The relationship between land use and land cover and streamflow was not significant. The reductions in the streamflow regimes over the years in the watershed were influenced by reductions in annual rainfall, which reduced about 19% while the water withdrawals from 2003 to 2014 increased 2350%. The results found in this study are useful to the water managers since they can estimate streamflow in any part of the studied river through rainfall and land use and land cover data. This helps to reduce the risks associated with the water allocation process.
Keywords: Multiple linear regression; Water allocation; Water resource management; Water scarcity.